Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It discloses auth requirements ('Public no-auth lookup'), latency expectations (milliseconds vs ~few seconds for custom domains), and the fact that it probes well-known platform endpoints in parallel. This is substantial behavioral context, though it does not cover failure modes or rate limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the primary action and auth status, then provides return format and field semantics. It includes the unnecessary phase label 'Phase 12 Wave 3 W3.1' which adds noise, but otherwise every sentence contributes value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite having no output schema, the description enumerates all return fields (platform, confidence, archive_method, forward_method, required_credentials, instructions) and explains how the key workflow fields are consumed. It also covers performance and auth, making it complete for a single-parameter tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already documents the url parameter with 100% coverage, including the hostname-match short-circuit behavior. The description adds no additional parameter-specific semantics; it only reiterates behavior already in the schema. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource: 'Detect the content platform behind a URL' and enumerates output platforms (Substack, Beehiiv, Ghost, Medium, Brevo, custom). It clearly distinguishes from sibling tools by focusing on platform identification and onboarding workflow rather than content retrieval or licensing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states 'Public no-auth lookup' and 'Given a URL, identifies what platform powers it,' which implies the use case. It also explains that the returned archive_method and forward_method are read by Opedd's setup wizard, giving strong context for when to use it. However, it does not explicitly contrast with sibling tools or state when not to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.